首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   29725篇
  免费   822篇
  国内免费   721篇
耳鼻咽喉   803篇
儿科学   383篇
妇产科学   345篇
基础医学   713篇
口腔科学   1034篇
临床医学   1675篇
内科学   2553篇
皮肤病学   122篇
神经病学   864篇
特种医学   867篇
外科学   14409篇
综合类   2856篇
一般理论   1篇
预防医学   767篇
眼科学   459篇
药学   1057篇
  11篇
中国医学   341篇
肿瘤学   2008篇
  2023年   355篇
  2022年   634篇
  2021年   1124篇
  2020年   733篇
  2019年   2492篇
  2018年   2288篇
  2017年   1354篇
  2016年   546篇
  2015年   684篇
  2014年   1501篇
  2013年   1263篇
  2012年   1300篇
  2011年   1399篇
  2010年   1199篇
  2009年   1130篇
  2008年   1063篇
  2007年   1027篇
  2006年   854篇
  2005年   728篇
  2004年   629篇
  2003年   625篇
  2002年   529篇
  2001年   497篇
  2000年   430篇
  1999年   377篇
  1998年   328篇
  1997年   234篇
  1996年   166篇
  1995年   172篇
  1994年   132篇
  1993年   98篇
  1992年   78篇
  1991年   63篇
  1990年   63篇
  1989年   76篇
  1988年   65篇
  1987年   63篇
  1985年   534篇
  1984年   521篇
  1983年   383篇
  1982年   460篇
  1981年   416篇
  1980年   436篇
  1979年   360篇
  1978年   353篇
  1977年   205篇
  1976年   375篇
  1975年   316篇
  1974年   282篇
  1973年   255篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
52.
53.
《Clinical lung cancer》2020,21(2):160-170
IntroductionPulmonary carcinosarcoma (PC) is a rare malignant neoplasm composed of epithelial and mesenchymal components. It accounts for < 1% of thoracic cancers and is not fully understood. This study examined Surveillance, Epidemiology, and End Results (SEER) data to describe demographic and clinical characteristics of patients with PC and assessed survival outcomes by treatment modality and stage.Patients and MethodsSEER data were reviewed to identify patients diagnosed with primary PC (1973-2012). Overall survival (OS) and disease-specific survival (DSS) were analyzed by univariate/multivariable Cox proportional hazards models and Kaplan-Meier methods.ResultsA total of 411 patients were included. Median age was 67 (range, 24-96) years. Disease stage at the time of initial diagnosis was known for 74.7% of the identified patients (307/411). Of these patients, 23.1% had localized disease. Survival was significantly better for patients with localized disease (OS: 31 vs. 6 months, P < .001; DSS: 54 vs. 8 months, P < .001). Additionally, patients who received surgery alone had significantly improved OS (20 months; P < .001) and DSS (32 months; P < .001) compared to patients who received combined surgery and radiotherapy (OS: 7 months; DSS: 8 months) or radiotherapy alone (OS: 4 months; DSS: 4 months).ConclusionTreatment with surgery alone resulted in superior survival outcomes compared to other treatment modality combinations, regardless of patient age and disease stage. Within the limitations of this study, providers may wish to consider these findings when devising patient treatment plans.  相似文献   
54.
《Clinical breast cancer》2020,20(6):454-461
BackgroundCoronavirus disease 2019 (COVID-19) has put a strain on regular healthcare worldwide. In the Netherlands, the national screening programs, including for breast cancer, were halted temporarily. This posed a challenge to breast cancer care, because ∼40% of cases are detected through national screening. Therefore, the aim of the present study was to evaluate the effects of the COVID-19 pandemic on the surgical care of patients with breast cancer in the Netherlands.Materials and MethodsThe present multicenter retrospective cohort study investigated the effects of COVID-19 on patients with breast cancer who had undergone surgery from March 9 to May 17, 2020. The primary endpoints were the number of surgical procedures performed during the study period, tumor characteristics, surgery type, and route of referral. The secondary endpoint was the incidence of postoperative complications during the study period.ResultsA total of 217 consecutive patients with breast cancer requiring surgery were included. We found an overall decrease in the number of patients with breast cancer who were undergoing surgery. The most significant decline was seen in surgery for T1-T2 and N0 tumors. A decline in the number of referrals from both the national screening program and general practitioners was observed. The incidence of postoperative complications remained stable during the study period.ConclusionsThe temporary halt of the national screening program for breast cancer resulted in fewer surgical procedures during the study period and a pronounced decrease in surgery of the lower tumor stages.  相似文献   
55.
BackgroundThe third most common bariatric surgery is revisional bariatric surgery. The American College of Surgeons tracks outcomes using the Metabolic and Bariatric Surgery Accreditation Quality Initiative Program database. We used this database to examine trends in revisional bariatric surgery.ObjectiveTo evaluate how trends in bariatric revisional surgery have changed in recent years.SettingUniversity Hospital, United States.MethodsThe Metabolic and Bariatric Surgery Accreditation Quality Initiative Program database for 2015 to 2017 was examined for revisions of bariatric surgery. Patients who underwent revisional bariatric surgery were identified by the primary Current Procedural Terminology code, the REVCONV and PREVIOUS_SURGERY field as well as secondary Current Procedural Terminology codes. There is no exact code for sleeve gastrectomy (SG) to laparoscopic Roux-en-Y gastric bypass (LRYGB), so we used 43644 (GB)+REVCONV+PREVIOUS_SURGERY for this.ResultsFor the years 2015 to 2017 there were 57,683 revisions/conversions of 528,081 patients. The number of revisions increased over the study period by 5213 cases. The most common revision was laparoscopic adjustable gastric band (LAGB) to SG with 15,433 cases and the second was LAGB to LRYGB with 10,485 cases. There were 14,715 LAGB removals. It is more difficult to track SG to LRYGB but there were 8491 unlisted cases, which may have been sleeve to bypass.ConclusionLAGBs are being taken out or converted, and this group makes up the largest portion of revisions and conversions. It is difficult to track SG to LRYGB, but the number of unlisted cases continues to climb. This will likely surpass LAGB conversions with time. The Metabolic and Bariatric Surgery Accreditation Quality Initiative Program should be modified to capture revisions/conversions of SG.  相似文献   
56.

Background

Controversy continues as to whether single-incision laparoscopic cholecystectomy, with the somewhat larger incision at the umbilicus, may lead to a worse postoperative quality of life and more pain compared with the more classic 4-port laparoscopic cholecystectomy. The aim of this study was to compare single-incision and 4-port laparoscopic cholecystectomy from the perspective of quality of life.

Methods

This study was a multicenter, parallel-group, open-label, randomized clinical trial. A total of 120 patients who were scheduled to undergo elective cholecystectomy were randomly assigned 1:1 into the single-incision laparoscopic cholecystectomy or the 4-port laparoscopic cholecystectomy group and then assessed continuously for 2 weeks during the postoperative period. The primary outcome was quality of life, defined as the time to resume normal daily activities. Postoperative pain was also assessed. To explore the heterogeneity of treatment effects, we assessed the interactions of sex, age, and working status on recovery time.

Results

A total of 58 patients in the single-incision group and 53 in the 4-port group (n?=?111, 47 male, mean age 57 years) were analyzed. The mean time to resume daily activities was 10.2 days and 8.8 days, respectively, for single-incision and 4-port laparoscopic cholecystectomy (95% confidence interval –0.4 to 3.2, P?=?.12). Similarly, the time to relief from postoperative pain did not differ significantly between the groups. Statistically insignificant but qualitative interactions were noted; in the subgroups of women, full-time workers, and patients younger than 60 years, recovery tended to be slower after single-incision laparoscopic cholecystectomy.

Conclusion

Postoperative quality of life did not differ substantially between single-incision laparoscopic cholecystectomy and 4-port laparoscopic cholecystectomy. Patients younger than 60 years, women, and full-time workers tended to have a somewhat slower recovery after single-incision laparoscopic cholecystectomy.  相似文献   
57.
《Clinical lung cancer》2020,21(5):443-449.e4
BackgroundTraditionally, elective nodal irradiation (ENI) has been used in clinical trials that have established thoracic radiotherapy as instrumental in improving survival for patients with limited-stage small-cell lung cancer (LS-SCLC). However, several reports have suggested that the omission of ENI might be appropriate. Current US practice patterns are unknown regarding ENI for patients with LS-SCLC.Materials and MethodsWe surveyed US radiation oncologists via an institutional review board-approved questionnaire. The questions covered demographics, treatment recommendations, and self-assessed knowledge of key clinical trials. χ2 and Cochran-Armitage tests were used to evaluate for statistically significant correlations between responses.ResultsWe received 309 responses. Of the respondents, 21% recommended ENI for N0 LS-SCLC, 29% for N1, and 30% for N2; 64% did not recommend ENI for any of these clinical scenarios. The respondents who recommended ENI were more likely to have been practicing for > 10 years (P < .001), more likely to be in private practice (P = .04), and less likely to be familiar with the ongoing Cancer and Leukemia Group B 30610 trial (P = .04). Almost all respondents (93%) prescribed the same radiation dose to the primary disease and involved lymph nodes. When delivering ENI, 36% prescribed the same dose to the involved and elective nodes, and 64% prescribed a lower dose to the elective nodes.ConclusionNearly two thirds of respondents did not recommend ENI, which represents a shift in practice. A recent large clinical trial that omitted ENI reported greater overall survival than previously reported and lower-than-expected radiation toxicities, lending further evidence that omitting ENI should be considered a standard treatment strategy.  相似文献   
58.
59.
ObjectivesSevere acute kidney injury (AKI) is a known risk factor for infection and mortality. However, whether stage 1 AKI is a risk factor for infection has not been evaluated in adults. We hypothesized that stage 1 AKI following cardiac surgery would independently associate with infection and mortality.MethodsIn this retrospective propensity score–matched study, we evaluated 1620 adult patients who underwent nonemergent cardiac surgery at the University of Colorado Hospital from 2011 to 2017. Patients who developed stage 1 AKI by Kidney Disease Improving Global Outcomes creatinine criteria within 72 hours of surgery were matched to patients who did not develop AKI. The primary outcome was an infection, defined as a new surgical-site infection, positive blood or urine culture, or development of pneumonia. Secondary outcomes included in-hospital mortality, stroke, and intensive care unit (ICU) and hospital length of stay (LOS).ResultsStage 1 AKI occurred in 293 patients (18.3%). Infection occurred in 20.9% of patients with stage 1 AKI compared with 8.1% in the no-AKI group (P < .001). In propensity-score matched analysis, stage 1 AKI independently associated with increased infection (odds ratio [OR]; 2.24, 95% confidence interval [CI], 1.37-3.17), ICU LOS (OR, 2.38; 95% CI, 1.71–3.31), and hospital LOS (OR, 1.30; 95% CI, 1.17-1.45).ConclusionsStage 1 AKI is independently associated with postoperative infection, ICU LOS, and hospital LOS. Treatment strategies focused on prevention, early recognition, and optimal medical management of AKI may decrease significant postoperative morbidity.  相似文献   
60.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号